516 OLOSSAMT. 



Pigment. — The coloring material produced generally in the super- 

 ficial parts of animals. The cells secreting it are called pigment- 

 cells. 



Pinnate. — Bearing leaflets on each side of a central stalk. 



Pistils. — The female organs of a flower, which occupy a position in 

 the center of the other floral organs. The pistil is generally 

 divisible into the ovary or germen, the style and the stigma. 



Placentalia, Placentata, or Placental Mammals. — See Mam 



MAI,IA. 



Plantigrades. — Quadrupeds which walk upon the whole sole of 

 the foot, like the Bears. 



Plastic. — Readily capable of change. 



Pleistocene Period. — Ths latest portion of the Tertiary epoch. 



Plumule (in plants).— The minute bud between the seed-leaves of 

 newly-germinated plants. 



Plutonic Rocks. — Rocks supposed to have been produced by 

 igneous action in the depths of the earth. 



Pollen. — The male element in flowering plants; usually a fine dust 

 produced by the anthers, which, by contact with the stigma 

 effects the fecundation of the seeds. This impregnation is 

 brought about by means of tubes {pollen-tubes) which issue from 

 the pollen-grains adhering to the stigma, and penetrate through 

 the tissues until they reach the ovary. 



Poltandrous (flowers). — Flowers having many stamens. 



POLYG.^MOUS Plants. — Plants in which some flowers are unisexual 

 and others hermaphrodite. The unisexual (male and female) 

 flowers, may be on the same or on different plants. 



Polymorphic. — Presenting many forms. 



PoLYZOARY. — The common structure formed by the cells of the 

 Polyzoa, such as the well-known Sea-mats. 



Prehensile. — Capable of grasping. 



Prepotent. — Having a superiority of power. 



Primaries. — The feathers forming the tip of the wing of a bird, and 

 inserted upon that part which represents the hand of man. 



Processes. — Projecting portions of bones, usually for the attach- 

 ment of muscles, ligaments, etc. 



Propolis. — A resinous material collected by the Hive-Bees from the 

 opening buds of various trees. 



Protean. — Exceedingly variable. 



Protozoa.— The lowest great division of the Animal Kingdom. 

 These animals are composed of a gelatinous material and show 

 scarcely any trace of distinct organs. The Infusoria, Foramini- 

 fera and Sponges, with some other forms, belong to this division. 



Pupa (pi. PuP/B) — The second stage in the development of an 

 Insect, from which it emerges in the perfect (winged) reproduc- 

 tive form. In most insects the pupal stage is passed in perfect 

 repose. The chrysalis is the pupal state of Butterflies. 



Ramus. — One half of the lower jaw in the Mammalia. The portion 

 which rises to articulate with the skull is called the ascending 



